Open an edit page, e.g. http://musicbrainz.org/edit/17468301
Click "Yes"
Write a note
Realise you don't actually want to enter a vote yet
Result: You can't submit the page without voting, because there's no "None" option and submitting an edit note will also submit your vote.

http://musicbrainz.org/edit/open does have a "None" option.